/* Copyright (c) 2000, 2013, Oracle and/or its affiliates.
   Copyright (c) 2009, 2020, MariaDB Corporation.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */

#include "strings_def.h"
#include <m_ctype.h>
#include <my_xml.h>

/*

  This files implements routines which parse XML based
  character set and collation description files.
  
  Unicode collations are encoded according to
  
    Unicode Technical Standard #35
    Locale Data Markup Language (LDML)
    http://www.unicode.org/reports/tr35/
  
  and converted into ICU string according to
  
    Collation Customization
    http://oss.software.ibm.com/icu/userguide/Collate_Customization.html
  
*/
const char charset_name_latin2[]= "latin2";
const char charset_name_utf8mb3[]= "utf8mb3";
const char charset_name_utf16[]= "utf16";
const char charset_name_utf32[]= "utf32";
const char charset_name_ucs2[]= "ucs2";
const char charset_name_utf8mb4[]= "utf8mb4";

/*
  Avoid using my_snprintf
  We cannot use my_snprintf() here, because ctype.o is
  used to build conf_to_src, which must require minimum
  dependency.
*/

#undef my_snprinf
#define my_snprintf "We cannot use my_snprintf in this file"


int (*my_string_stack_guard)(int)= NULL;

static char *mstr(char *str,const char *src,size_t l1,size_t l2)
{
  l1= l1<l2 ? l1 : l2;
  memcpy(str,src,l1);
  str[l1]='\0';
  return str;
}

struct my_cs_file_section_st
{
  int        state;
  const char *str;
};

#define _CS_MISC	1
#define _CS_ID		2
#define _CS_CSNAME	3
#define _CS_FAMILY	4
#define _CS_ORDER	5
#define _CS_COLNAME	6
#define _CS_FLAG	7
#define _CS_CHARSET	8
#define _CS_COLLATION	9
#define _CS_UPPERMAP	10
#define _CS_LOWERMAP	11
#define _CS_UNIMAP	12
#define _CS_COLLMAP	13
#define _CS_CTYPEMAP	14
#define _CS_PRIMARY_ID	15
#define _CS_BINARY_ID	16
#define _CS_CSDESCRIPT	17


/* Special purpose commands */
#define _CS_UCA_VERSION                 100
#define _CS_CL_SUPPRESS_CONTRACTIONS    101
#define _CS_CL_OPTIMIZE                 102
#define _CS_CL_SHIFT_AFTER_METHOD       103
#define _CS_CL_RULES_IMPORT             104
#define _CS_CL_RULES_IMPORT_SOURCE      105


/* Collation Settings */
#define _CS_ST_SETTINGS                 200
#define _CS_ST_STRENGTH                 201
#define _CS_ST_ALTERNATE                202
#define _CS_ST_BACKWARDS                203
#define _CS_ST_NORMALIZATION            204
#define _CS_ST_CASE_LEVEL               205
#define _CS_ST_CASE_FIRST               206
#define _CS_ST_HIRAGANA_QUATERNARY      207
#define _CS_ST_NUMERIC                  208
#define _CS_ST_VARIABLE_TOP             209
#define _CS_ST_MATCH_BOUNDARIES         210
#define _CS_ST_MATCH_STYLE              211


/* Rules */
#define _CS_RULES                       300
#define _CS_RESET                       301
#define _CS_DIFF1                       302
#define _CS_DIFF2                       303
#define _CS_DIFF3                       304
#define _CS_DIFF4                       305
#define _CS_IDENTICAL                   306

/* Rules: Expansions */
#define _CS_EXP_X                       320
#define _CS_EXP_EXTEND                  321
#define _CS_EXP_DIFF1                   322
#define _CS_EXP_DIFF2                   323
#define _CS_EXP_DIFF3                   324
#define _CS_EXP_DIFF4                   325
#define _CS_EXP_IDENTICAL               326

/* Rules: Abbreviating Ordering Specifications */
#define _CS_A_DIFF1                     351
#define _CS_A_DIFF2                     352
#define _CS_A_DIFF3                     353
#define _CS_A_DIFF4                     354
#define _CS_A_IDENTICAL                 355

/* Rules: previous context */
#define _CS_CONTEXT                     370

/* Rules: Placing Characters Before Others*/
#define _CS_RESET_BEFORE 380

/* Rules: Logical Reset Positions */
#define _CS_RESET_FIRST_PRIMARY_IGNORABLE     401
#define _CS_RESET_LAST_PRIMARY_IGNORABLE      402
#define _CS_RESET_FIRST_SECONDARY_IGNORABLE   403
#define _CS_RESET_LAST_SECONDARY_IGNORABLE    404
#define _CS_RESET_FIRST_TERTIARY_IGNORABLE    405
#define _CS_RESET_LAST_TERTIARY_IGNORABLE     406
#define _CS_RESET_FIRST_TRAILING              407
#define _CS_RESET_LAST_TRAILING               408
#define _CS_RESET_FIRST_VARIABLE              409
#define _CS_RESET_LAST_VARIABLE               410
#define _CS_RESET_FIRST_NON_IGNORABLE         411
#define _CS_RESET_LAST_NON_IGNORABLE          412



static const struct my_cs_file_section_st sec[] =
{
  {_CS_MISC,		"xml"},
  {_CS_MISC,		"xml/version"},
  {_CS_MISC,		"xml/encoding"},
  {_CS_MISC,		"charsets"},
  {_CS_MISC,		"charsets/max-id"},
  {_CS_MISC,		"charsets/copyright"},
  {_CS_MISC,		"charsets/description"},
  {_CS_CHARSET,		"charsets/charset"},
  {_CS_PRIMARY_ID,	"charsets/charset/primary-id"},
  {_CS_BINARY_ID,	"charsets/charset/binary-id"},
  {_CS_CSNAME,		"charsets/charset/name"},
  {_CS_FAMILY,		"charsets/charset/family"},
  {_CS_CSDESCRIPT,	"charsets/charset/description"},
  {_CS_MISC,		"charsets/charset/alias"},
  {_CS_MISC,		"charsets/charset/ctype"},
  {_CS_CTYPEMAP,	"charsets/charset/ctype/map"},
  {_CS_MISC,		"charsets/charset/upper"},
  {_CS_UPPERMAP,	"charsets/charset/upper/map"},
  {_CS_MISC,		"charsets/charset/lower"},
  {_CS_LOWERMAP,	"charsets/charset/lower/map"},
  {_CS_MISC,		"charsets/charset/unicode"},
  {_CS_UNIMAP,		"charsets/charset/unicode/map"},
  {_CS_COLLATION,	"charsets/charset/collation"},
  {_CS_COLNAME,		"charsets/charset/collation/name"},
  {_CS_ID,		"charsets/charset/collation/id"},
  {_CS_ORDER,		"charsets/charset/collation/order"},
  {_CS_FLAG,		"charsets/charset/collation/flag"},
  {_CS_COLLMAP,		"charsets/charset/collation/map"},

  /* Special purpose commands */
  {_CS_UCA_VERSION,              "charsets/charset/collation/version"},
  {_CS_CL_SUPPRESS_CONTRACTIONS, "charsets/charset/collation/suppress_contractions"},
  {_CS_CL_OPTIMIZE,              "charsets/charset/collation/optimize"},
  {_CS_CL_SHIFT_AFTER_METHOD,    "charsets/charset/collation/shift-after-method"},
  {_CS_CL_RULES_IMPORT,          "charsets/charset/collation/rules/import"},
  {_CS_CL_RULES_IMPORT_SOURCE,   "charsets/charset/collation/rules/import/source"},

  /* Collation Settings */
  {_CS_ST_SETTINGS,              "charsets/charset/collation/settings"},
  {_CS_ST_STRENGTH,              "charsets/charset/collation/settings/strength"},
  {_CS_ST_ALTERNATE,             "charsets/charset/collation/settings/alternate"},
  {_CS_ST_BACKWARDS,             "charsets/charset/collation/settings/backwards"},
  {_CS_ST_NORMALIZATION,         "charsets/charset/collation/settings/normalization"},
  {_CS_ST_CASE_LEVEL,            "charsets/charset/collation/settings/caseLevel"},
  {_CS_ST_CASE_FIRST,            "charsets/charset/collation/settings/caseFirst"},
  {_CS_ST_HIRAGANA_QUATERNARY,   "charsets/charset/collation/settings/hiraganaQuaternary"},
  {_CS_ST_NUMERIC,               "charsets/charset/collation/settings/numeric"},
  {_CS_ST_VARIABLE_TOP,          "charsets/charset/collation/settings/variableTop"},
  {_CS_ST_MATCH_BOUNDARIES,      "charsets/charset/collation/settings/match-boundaries"},
  {_CS_ST_MATCH_STYLE,           "charsets/charset/collation/settings/match-style"},

  /* Rules */
  {_CS_RULES,           "charsets/charset/collation/rules"},
  {_CS_RESET,           "charsets/charset/collation/rules/reset"},
  {_CS_DIFF1,           "charsets/charset/collation/rules/p"},
  {_CS_DIFF2,           "charsets/charset/collation/rules/s"},
  {_CS_DIFF3,           "charsets/charset/collation/rules/t"},
  {_CS_DIFF4,           "charsets/charset/collation/rules/q"},
  {_CS_IDENTICAL,       "charsets/charset/collation/rules/i"},

  /* Rules: expansions */
  {_CS_EXP_X,           "charsets/charset/collation/rules/x"},
  {_CS_EXP_EXTEND,      "charsets/charset/collation/rules/x/extend"},
  {_CS_EXP_DIFF1,       "charsets/charset/collation/rules/x/p"},
  {_CS_EXP_DIFF2,       "charsets/charset/collation/rules/x/s"},
  {_CS_EXP_DIFF3,       "charsets/charset/collation/rules/x/t"},
  {_CS_EXP_DIFF4,       "charsets/charset/collation/rules/x/q"},
  {_CS_EXP_IDENTICAL,   "charsets/charset/collation/rules/x/i"},
  
  /* Rules: previous context */
  {_CS_CONTEXT,         "charsets/charset/collation/rules/x/context"},

  /* Rules: Abbreviating Ordering Specifications */
  {_CS_A_DIFF1,         "charsets/charset/collation/rules/pc"},
  {_CS_A_DIFF2,         "charsets/charset/collation/rules/sc"},
  {_CS_A_DIFF3,         "charsets/charset/collation/rules/tc"},
  {_CS_A_DIFF4,         "charsets/charset/collation/rules/qc"},
  {_CS_A_IDENTICAL,     "charsets/charset/collation/rules/ic"},

  /* Rules: Placing Characters Before Others*/
  {_CS_RESET_BEFORE,    "charsets/charset/collation/rules/reset/before"},

  /* Rules: Logical Reset Positions */
  {_CS_RESET_FIRST_NON_IGNORABLE,       "charsets/charset/collation/rules/reset/first_non_ignorable"},
  {_CS_RESET_LAST_NON_IGNORABLE,        "charsets/charset/collation/rules/reset/last_non_ignorable"},
  {_CS_RESET_FIRST_PRIMARY_IGNORABLE,   "charsets/charset/collation/rules/reset/first_primary_ignorable"},
  {_CS_RESET_LAST_PRIMARY_IGNORABLE,    "charsets/charset/collation/rules/reset/last_primary_ignorable"},
  {_CS_RESET_FIRST_SECONDARY_IGNORABLE, "charsets/charset/collation/rules/reset/first_secondary_ignorable"},
  {_CS_RESET_LAST_SECONDARY_IGNORABLE,  "charsets/charset/collation/rules/reset/last_secondary_ignorable"},
  {_CS_RESET_FIRST_TERTIARY_IGNORABLE,  "charsets/charset/collation/rules/reset/first_tertiary_ignorable"},
  {_CS_RESET_LAST_TERTIARY_IGNORABLE,   "charsets/charset/collation/rules/reset/last_tertiary_ignorable"},
  {_CS_RESET_FIRST_TRAILING,            "charsets/charset/collation/rules/reset/first_trailing"},
  {_CS_RESET_LAST_TRAILING,             "charsets/charset/collation/rules/reset/last_trailing"},
  {_CS_RESET_FIRST_VARIABLE,            "charsets/charset/collation/rules/reset/first_variable"},
  {_CS_RESET_LAST_VARIABLE,             "charsets/charset/collation/rules/reset/last_variable"},

  {0,	NULL}
};

static const struct my_cs_file_section_st
*cs_file_sec(const char *attr, size_t len)
{
  const struct my_cs_file_section_st *s;
  for (s=sec; s->str; s++)
  {
    if (!strncmp(attr, s->str, len) && s->str[len] == 0)
      return s;
  }
  return NULL;
}

#define MY_CS_CSDESCR_SIZE	64
#define MY_CS_TAILORING_SIZE	(32*1024)
#define MY_CS_UCA_VERSION_SIZE  64
#define MY_CS_CONTEXT_SIZE      64

typedef struct my_cs_file_info
{
  char   csname[MY_CS_CHARACTER_SET_NAME_SIZE];
  char   name[MY_CS_COLLATION_NAME_SIZE];
  uchar  ctype[MY_CS_CTYPE_TABLE_SIZE];
  uchar  to_lower[MY_CS_TO_LOWER_TABLE_SIZE];
  uchar  to_upper[MY_CS_TO_UPPER_TABLE_SIZE];
  uchar  sort_order[MY_CS_SORT_ORDER_TABLE_SIZE];
  uint16 tab_to_uni[MY_CS_TO_UNI_TABLE_SIZE];
  char   comment[MY_CS_CSDESCR_SIZE];
  char  *tailoring;
  size_t tailoring_length;
  size_t tailoring_alloced_length;
  char   context[MY_CS_CONTEXT_SIZE];
  struct charset_info_st cs;
  MY_CHARSET_LOADER *loader;
} MY_CHARSET_FILE;


static void
my_charset_file_reset_charset(MY_CHARSET_FILE *i)
{
  memset(&i->cs, 0, sizeof(i->cs));
}


static void
my_charset_file_reset_collation(MY_CHARSET_FILE *i)
{
  i->tailoring_length= 0;
  i->context[0]= '\0';
}


static void
my_charset_file_init(MY_CHARSET_FILE *i)
{
  my_charset_file_reset_charset(i);
  my_charset_file_reset_collation(i);
  i->tailoring= NULL;
  i->tailoring_alloced_length= 0;
}


static void
my_charset_file_free(MY_CHARSET_FILE *i)
{
  i->loader->free(i->tailoring);
}


static int
my_charset_file_tailoring_realloc(MY_CHARSET_FILE *i, size_t newlen)
{
  if (i->tailoring_alloced_length > newlen ||
     (i->tailoring= i->loader->realloc(i->tailoring,
                                       (i->tailoring_alloced_length=
                                        (newlen + 32*1024)))))
  {
    return MY_XML_OK;
  }
  return MY_XML_ERROR;
}


static int fill_uchar(uchar *a,uint size,const char *str, size_t len)
{
  uint i= 0;
  const char *s, *b, *e=str+len;
  
  for (s=str ; s < e ; i++)
  { 
    for ( ; (s < e) && strchr(" \t\r\n",s[0]); s++) ;
    b=s;
    for ( ; (s < e) && !strchr(" \t\r\n",s[0]); s++) ;
    if (s == b || i > size)
      break;
    a[i]= (uchar) strtoul(b,NULL,16);
  }
  return 0;
}

static int fill_uint16(uint16 *a,uint size,const char *str, size_t len)
{
  uint i= 0;
  
  const char *s, *b, *e=str+len;
  for (s=str ; s < e ; i++)
  { 
    for ( ; (s < e) && strchr(" \t\r\n",s[0]); s++) ;
    b=s;
    for ( ; (s < e) && !strchr(" \t\r\n",s[0]); s++) ;
    if (s == b || i > size)
      break;
    a[i]= (uint16) strtol(b,NULL,16);
  }
  return 0;
}




static int
tailoring_append(MY_XML_PARSER *st,
                 const char *fmt, size_t len, const char *attr)
{
  struct my_cs_file_info *i= (struct my_cs_file_info *) st->user_data;
  size_t newlen= i->tailoring_length + len + 64; /* 64 for format */ 
  if (MY_XML_OK == my_charset_file_tailoring_realloc(i, newlen))
  {
    char *dst= i->tailoring + i->tailoring_length;
    sprintf(dst, fmt, (int) len, attr);
    i->tailoring_length+= strlen(dst);
    return MY_XML_OK;
  }
  return MY_XML_ERROR;
}


static int
tailoring_append2(MY_XML_PARSER *st,
                  const char *fmt,
                  size_t len1, const char *attr1,
                  size_t len2, const char *attr2)
{
  struct my_cs_file_info *i= (struct my_cs_file_info *) st->user_data;
  size_t newlen= i->tailoring_length + len1 + len2 + 64; /* 64 for format */
  if (MY_XML_OK == my_charset_file_tailoring_realloc(i, newlen))
  {
    char *dst= i->tailoring + i->tailoring_length;
    sprintf(dst, fmt, (int) len1, attr1, (int) len2, attr2);
    i->tailoring_length+= strlen(dst);
    return MY_XML_OK;
  }
  return MY_XML_ERROR;
}


static size_t
scan_one_character(const char *s, const char *e, my_wc_t *wc)
{
  CHARSET_INFO *cs= &my_charset_utf8mb3_general_ci;
  if (s >= e)
    return 0;

  /* Escape sequence: \uXXXX */
  if (s[0] == '\\' && s + 2 < e && s[1] == 'u' && my_isxdigit(cs, s[2]))
  {
    size_t len= 3; /* We have at least one digit */
    for (s+= 3; s < e && my_isxdigit(cs, s[0]); s++, len++)
    {
    }
    wc[0]= 0;
    return len;
  }
  else if ((int8) s[0] > 0) /* 7-bit character */
  {
    wc[0]= 0;
    return 1;
  }
  else /* Non-escaped character */
  {
    int rc= my_ci_mb_wc(cs, wc, (uchar *) s, (uchar *) e);
    if (rc > 0)
      return (size_t) rc;
  }
  return 0;
}


static int
tailoring_append_abbreviation(MY_XML_PARSER *st,
                              const char *fmt, size_t len, const char *attr)
{
  size_t clen;
  const char *attrend= attr + len;
  my_wc_t wc;

  for ( ; (clen= scan_one_character(attr, attrend, &wc)) > 0; attr+= clen)
  {
    DBUG_ASSERT(attr < attrend);
    if (tailoring_append(st, fmt, clen, attr) != MY_XML_OK)
      return MY_XML_ERROR;
  }
  return MY_XML_OK;
}


static int cs_enter(MY_XML_PARSER *st,const char *attr, size_t len)
{
  struct my_cs_file_info *i= (struct my_cs_file_info *)st->user_data;
  const struct my_cs_file_section_st *s= cs_file_sec(attr,len);
  int state= s ? s->state : 0;
  
  switch (state) {
  case 0:
    i->loader->reporter(WARNING_LEVEL, "Unknown LDML tag: '%.*s'", len, attr);
    break;

  case _CS_CHARSET:
    my_charset_file_reset_charset(i);
    break;

  case _CS_COLLATION:
    my_charset_file_reset_collation(i);
    break;

  case _CS_RESET:
    return tailoring_append(st, " &", 0, NULL);

  default:
    break;
  }
  return MY_XML_OK;
}


static int cs_leave(MY_XML_PARSER *st,const char *attr, size_t len)
{
  struct my_cs_file_info *i= (struct my_cs_file_info *)st->user_data;
  const struct my_cs_file_section_st *s= cs_file_sec(attr,len);
  int    state= s ? s->state : 0;
  int    rc;
  
  switch(state){
  case _CS_COLLATION:
    if (i->tailoring_length)
      i->cs.tailoring= i->tailoring;
    rc= i->loader->add_collation ? i->loader->add_collation(&i->cs) : MY_XML_OK;
    break;

  /* Rules: Logical Reset Positions */
  case _CS_RESET_FIRST_NON_IGNORABLE:
    rc= tailoring_append(st, "[first non-ignorable]", 0, NULL);
    break;

  case _CS_RESET_LAST_NON_IGNORABLE:
    rc= tailoring_append(st, "[last non-ignorable]", 0, NULL);
    break;

  case _CS_RESET_FIRST_PRIMARY_IGNORABLE:
    rc= tailoring_append(st, "[first primary ignorable]", 0, NULL);
    break;

  case _CS_RESET_LAST_PRIMARY_IGNORABLE:
    rc= tailoring_append(st, "[last primary ignorable]", 0, NULL);
    break;

  case _CS_RESET_FIRST_SECONDARY_IGNORABLE:
    rc= tailoring_append(st, "[first secondary ignorable]", 0, NULL);
    break;

  case _CS_RESET_LAST_SECONDARY_IGNORABLE:
    rc= tailoring_append(st, "[last secondary ignorable]", 0, NULL);
    break;

  case _CS_RESET_FIRST_TERTIARY_IGNORABLE:
    rc= tailoring_append(st, "[first tertiary ignorable]", 0, NULL);
    break;

  case _CS_RESET_LAST_TERTIARY_IGNORABLE:
    rc= tailoring_append(st, "[last tertiary ignorable]", 0, NULL);
    break;

  case _CS_RESET_FIRST_TRAILING:
    rc= tailoring_append(st, "[first trailing]", 0, NULL);
    break;

  case _CS_RESET_LAST_TRAILING:
    rc= tailoring_append(st, "[last trailing]", 0, NULL);
    break;

  case _CS_RESET_FIRST_VARIABLE:
    rc= tailoring_append(st, "[first variable]", 0, NULL);
    break;

  case _CS_RESET_LAST_VARIABLE:
    rc= tailoring_append(st, "[last variable]", 0, NULL);
    break;

  default:
    rc=MY_XML_OK;
  }
  return rc;
}


static const char *diff_fmt[5]=
{
  "<%.*s",
  "<<%.*s",
  "<<<%.*s",
  "<<<<%.*s",
  "=%.*s"
};


static const char *context_diff_fmt[5]=
{
  "<%.*s|%.*s",
  "<<%.*s|%.*s",
  "<<<%.*s|%.*s",
  "<<<<%.*s|%.*s",
  "=%.*s|%.*s"
};


static int cs_value(MY_XML_PARSER *st,const char *attr, size_t len)
{
  struct my_cs_file_info *i= (struct my_cs_file_info *)st->user_data;
  const struct my_cs_file_section_st *s;
  int    state= (int)((s= cs_file_sec(st->attr.start,
                                      st->attr.end - st->attr.start)) ?
                      s->state : 0);
  int rc= MY_XML_OK;

  switch (state) {
  case _CS_MISC:
  case _CS_FAMILY:
  case _CS_ORDER:
    break;
  case _CS_ID:
    i->cs.number= strtol(attr,(char**)NULL,10);
    break;
  case _CS_BINARY_ID:
    i->cs.binary_number= strtol(attr,(char**)NULL,10);
    break;
  case _CS_PRIMARY_ID:
    i->cs.primary_number= strtol(attr,(char**)NULL,10);
    break;
  case _CS_COLNAME:
    i->cs.coll_name.str= mstr(i->name,attr,len,MY_CS_COLLATION_NAME_SIZE-1);
    i->cs.coll_name.length= strlen(i->cs.coll_name.str);
    break;
  case _CS_CSNAME:
    i->cs.cs_name.str= mstr(i->csname,attr,len,MY_CS_CHARACTER_SET_NAME_SIZE-1);
    i->cs.cs_name.length= strlen(i->cs.cs_name.str);
    break;
  case _CS_CSDESCRIPT:
    i->cs.comment=mstr(i->comment,attr,len,MY_CS_CSDESCR_SIZE-1);
    break;
  case _CS_FLAG:
    if (!strncmp("primary",attr,len))
      i->cs.state|= MY_CS_PRIMARY;
    else if (!strncmp("binary",attr,len))
      i->cs.state|= MY_CS_BINSORT;
    else if (!strncmp("compiled",attr,len))
      i->cs.state|= MY_CS_COMPILED;
    else if (!strncmp("nopad",attr,len))
      i->cs.state|= MY_CS_NOPAD;
    break;
  case _CS_UPPERMAP:
    fill_uchar(i->to_upper,MY_CS_TO_UPPER_TABLE_SIZE,attr,len);
    i->cs.to_upper=i->to_upper;
    break;
  case _CS_LOWERMAP:
    fill_uchar(i->to_lower,MY_CS_TO_LOWER_TABLE_SIZE,attr,len);
    i->cs.to_lower=i->to_lower;
    break;
  case _CS_UNIMAP:
    fill_uint16(i->tab_to_uni,MY_CS_TO_UNI_TABLE_SIZE,attr,len);
    i->cs.tab_to_uni=i->tab_to_uni;
    break;
  case _CS_COLLMAP:
    fill_uchar(i->sort_order,MY_CS_SORT_ORDER_TABLE_SIZE,attr,len);
    i->cs.sort_order=i->sort_order;
    break;
  case _CS_CTYPEMAP:
    fill_uchar(i->ctype,MY_CS_CTYPE_TABLE_SIZE,attr,len);
    i->cs.m_ctype=i->ctype;
    break;

  /* Special purpose commands */
  case _CS_UCA_VERSION:
    rc= tailoring_append(st, "[version %.*s]", len, attr);
    break;

  case _CS_CL_RULES_IMPORT_SOURCE:
    rc= tailoring_append(st, "[import %.*s]", len, attr);
    break;

  case _CS_CL_SUPPRESS_CONTRACTIONS:
    rc= tailoring_append(st, "[suppress contractions %.*s]", len, attr);
    break;

  case _CS_CL_OPTIMIZE:
    rc= tailoring_append(st, "[optimize %.*s]", len, attr);
    break;

  case _CS_CL_SHIFT_AFTER_METHOD:
    rc= tailoring_append(st, "[shift-after-method %.*s]", len, attr);
    break;

  /* Collation Settings */
  case _CS_ST_STRENGTH:
    /* 1, 2, 3, 4, 5, or primary, secondary, tertiary, quaternary, identical */
    rc= tailoring_append(st, "[strength %.*s]", len, attr);
    if (len && attr[0] >= '1' && attr[0] <= '9')
    {
      uint strength= attr[0] - '0';
      my_ci_set_strength(&i->cs, MY_MIN(strength, MY_UCA_WEIGHT_LEVELS));
    }
    break;

  case _CS_ST_ALTERNATE:
    /* non-ignorable, shifted */
    rc= tailoring_append(st, "[alternate %.*s]", len, attr);
    break;

  case _CS_ST_BACKWARDS:
    /* on, off, 2 */
    rc= tailoring_append(st, "[backwards %.*s]", len, attr);
    break;

  case _CS_ST_NORMALIZATION:
    /*
      TODO for WL#896: check collations for normalization: vi.xml
      We want precomposed characters work well at this point.
    */
    /* on, off */
    rc= tailoring_append(st, "[normalization %.*s]", len, attr);
    break;

  case _CS_ST_CASE_LEVEL:
    /* on, off */
    rc= tailoring_append(st, "[caseLevel %.*s]", len, attr);
    break;

  case _CS_ST_CASE_FIRST:
    /* upper, lower, off */
    rc= tailoring_append(st, "[caseFirst %.*s]", len, attr);
    break;

  case _CS_ST_HIRAGANA_QUATERNARY:
    /* on, off */
    rc= tailoring_append(st, "[hiraganaQ %.*s]", len, attr);
    break;

  case _CS_ST_NUMERIC:
    /* on, off */
    rc= tailoring_append(st, "[numeric %.*s]", len, attr);
    break;

  case _CS_ST_VARIABLE_TOP:
    /* TODO for WL#896: check value format */
    rc= tailoring_append(st, "[variableTop %.*s]", len, attr);
    break;

  case _CS_ST_MATCH_BOUNDARIES:
    /* none, whole-character, whole-word */
    rc= tailoring_append(st, "[match-boundaries %.*s]", len, attr);
    break;

  case _CS_ST_MATCH_STYLE:
    /* minimal, medial, maximal */
    rc= tailoring_append(st, "[match-style %.*s]", len, attr);
    break;


  /* Rules */
  case _CS_RESET:
    rc= tailoring_append(st, "%.*s", len, attr);
    break;

  case _CS_DIFF1:
  case _CS_DIFF2:
  case _CS_DIFF3:
  case _CS_DIFF4:
  case _CS_IDENTICAL:
    rc= tailoring_append(st, diff_fmt[state - _CS_DIFF1], len, attr);
    break;


  /* Rules: Expansion */
  case _CS_EXP_EXTEND:
    rc= tailoring_append(st, " / %.*s", len, attr);
    break;

  case _CS_EXP_DIFF1:
  case _CS_EXP_DIFF2:
  case _CS_EXP_DIFF3:
  case _CS_EXP_DIFF4:
  case _CS_EXP_IDENTICAL:
    if (i->context[0])
    {
      rc= tailoring_append2(st, context_diff_fmt[state - _CS_EXP_DIFF1],
                            strlen(i->context), i->context, len, attr);
      i->context[0]= 0;
    }
    else
      rc= tailoring_append(st, diff_fmt[state  - _CS_EXP_DIFF1], len, attr);
    break;

  /* Rules: Context */
  case _CS_CONTEXT:
    if (len < sizeof(i->context))
    {
      memcpy(i->context, attr, len);
      i->context[len]= '\0';
    }
    break;

  /* Rules: Abbreviating Ordering Specifications */
  case _CS_A_DIFF1:
  case _CS_A_DIFF2:
  case _CS_A_DIFF3:
  case _CS_A_DIFF4:
  case _CS_A_IDENTICAL:
    rc= tailoring_append_abbreviation(st, diff_fmt[state - _CS_A_DIFF1], len, attr);
    break;

  /* Rules: Placing Characters Before Others */
  case _CS_RESET_BEFORE:
    /*
      TODO for WL#896: Add this check into text customization parser:
      It is an error if the strength of the before relation is not identical
      to the relation after the reset. We'll need this for WL#896.
    */
    rc= tailoring_append(st, "[before %.*s]", len, attr);
    break;


  default:
    break;
  }

  return rc;
}


my_bool
my_parse_charset_xml(MY_CHARSET_LOADER *loader, const char *buf, size_t len)
{
  MY_XML_PARSER p;
  struct my_cs_file_info info;
  my_bool rc;
  
  my_charset_file_init(&info);
  my_xml_parser_create(&p);
  my_xml_set_enter_handler(&p,cs_enter);
  my_xml_set_value_handler(&p,cs_value);
  my_xml_set_leave_handler(&p,cs_leave);
  info.loader= loader;
  my_xml_set_user_data(&p, (void *) &info);
  rc= (my_xml_parse(&p,buf,len) == MY_XML_OK) ? FALSE : TRUE;
  my_xml_parser_free(&p);
  my_charset_file_free(&info);
  if (rc != MY_XML_OK)
  {
    const char *errstr= my_xml_error_string(&p);
    if (sizeof(loader->error) > 32 + strlen(errstr))
    {
      /* We cannot use my_snprintf() here. See previous comment. */
      sprintf(loader->error, "at line %d pos %d: %s",
                my_xml_error_lineno(&p)+1,
                (int) my_xml_error_pos(&p),
                my_xml_error_string(&p));
    }
  }
  return rc;
}


uint
my_string_repertoire_8bit(CHARSET_INFO *cs, const char *str, size_t length)
{
  const char *strend;
  if ((cs->state & MY_CS_NONASCII) && length > 0)
    return MY_REPERTOIRE_UNICODE30;
  if (!str) // Avoid UBSAN nullptr-with-offset
    return MY_REPERTOIRE_ASCII;
  for (strend= str + length; str < strend; str++)
  {
    if (((uchar) *str) > 0x7F)
      return MY_REPERTOIRE_UNICODE30;
  }
  return MY_REPERTOIRE_ASCII;
}


static void
my_string_metadata_init(MY_STRING_METADATA *metadata)
{
  metadata->repertoire= MY_REPERTOIRE_ASCII;
  metadata->char_length= 0;
}


/**
  This should probably eventually go as a virtual function into
  MY_CHARSET_HANDLER or MY_COLLATION_HANDLER.
*/
static void
my_string_metadata_get_mb(MY_STRING_METADATA *metadata,
                          CHARSET_INFO *cs, const char *str, ulong length)
{
  const char *strend= str ? str + length : NULL; // Avoid UB nullptr+0
  for (my_string_metadata_init(metadata) ;
       str < strend;
       metadata->char_length++)
  {
    my_wc_t wc;
    int mblen= my_ci_mb_wc(cs, &wc, (const uchar *) str, (const uchar *) strend);
    if (mblen > 0) /* Assigned character */
    {
      if (wc > 0x7F)
        metadata->repertoire|= MY_REPERTOIRE_EXTENDED;
      str+= mblen;
    }
    else if (mblen == MY_CS_ILSEQ) /* Bad byte sequence */
    {
      metadata->repertoire|= MY_REPERTOIRE_EXTENDED;
      str++;
    }
    else if (mblen > MY_CS_TOOSMALL) /* Unassigned character */ 
    {
      metadata->repertoire|= MY_REPERTOIRE_EXTENDED;
      str+= (-mblen);
    }
    else /* Incomplete character, premature end-of-line */
    {
      metadata->repertoire|= MY_REPERTOIRE_EXTENDED; /* Just in case */
      break;
    }
  }
}


/**
  Collect string metadata: length in characters and repertoire.
*/
void
my_string_metadata_get(MY_STRING_METADATA *metadata,
                       CHARSET_INFO *cs, const char *str, size_t length)
{
  if (cs->mbmaxlen == 1 && !(cs->state & MY_CS_NONASCII))
  {
    metadata->char_length= length;
    metadata->repertoire= my_string_repertoire_8bit(cs, str, (ulong)length);
  }
  else
  {
    my_string_metadata_get_mb(metadata, cs, str, (ulong)length);
  }
}


/*
  Check repertoire: detect pure ascii strings
*/
my_repertoire_t
my_string_repertoire(CHARSET_INFO *cs, const char *str, size_t length)
{
  if (cs->mbminlen == 1 && !(cs->state & MY_CS_NONASCII))
  {
    return my_string_repertoire_8bit(cs, str, length);
  }
  else
  {
    const char *strend= str + length;
    my_wc_t wc;
    int chlen;
    for (;
         (chlen= my_ci_mb_wc(cs, &wc, (uchar*) str, (uchar*) strend)) > 0;
         str+= chlen)
    {
      if (wc > 0x7F)
        return MY_REPERTOIRE_UNICODE30;
    }
  }
  return MY_REPERTOIRE_ASCII;
}


/*
  Returns repertoire for charset
*/
my_repertoire_t my_charset_repertoire(CHARSET_INFO *cs)
{
  return cs->state & MY_CS_PUREASCII ?
    MY_REPERTOIRE_ASCII : MY_REPERTOIRE_UNICODE30;
}


/*
  Detect whether a character set is ASCII compatible.

  Returns TRUE for:
  
  - all 8bit character sets whose Unicode mapping of 0x7B is '{'
    (ignores swe7 which maps 0x7B to "LATIN LETTER A WITH DIAERESIS")
  
  - all multi-byte character sets having mbminlen == 1
    (ignores ucs2 whose mbminlen is 2)
  
  TODO:
  
  When merging to 5.2, this function should be changed
  to check a new flag MY_CS_NONASCII, 
  
     return (cs->flag & MY_CS_NONASCII) ? 0 : 1;
  
  This flag was previously added into 5.2 under terms
  of WL#3759 "Optimize identifier conversion in client-server protocol"
  especially to mark character sets not compatible with ASCII.
  
  We won't backport this flag to 5.0 or 5.1.
  This function is Ok for 5.0 and 5.1, because we're not going
  to introduce new tricky character sets between 5.0 and 5.2.
*/
my_bool
my_charset_is_ascii_based(CHARSET_INFO *cs)
{
  return 
    (cs->mbmaxlen == 1 && cs->tab_to_uni && cs->tab_to_uni['{'] == '{') ||
    (cs->mbminlen == 1 && cs->mbmaxlen > 1);
}


/**
  Detect if a Unicode code point is printable.
*/
static inline my_bool
my_is_printable(my_wc_t wc)
{
  /*
    Blocks:
      U+0000 .. U+001F     control
      U+0020 .. U+007E     printable
      U+007F .. U+009F     control
      U+00A0 .. U+00FF     printable
      U+0100 .. U+10FFFF   As of Unicode-6.1.0, this range does not have any
                           characters of the "Cc" (Other, control) category.
                           Should be mostly safe to print.
                           Except for the surrogate halfs,
                           which are encoding components, not real characters.
  */
  if (wc >= 0x20 && wc <= 0x7E) /* Quickly detect ASCII printable */
    return TRUE;
  if (wc <= 0x9F)    /* The rest of U+0000..U+009F are control characters */
  {
    /* NL, CR, TAB are Ok */
    return (wc == '\r' || wc == '\n' || wc == '\t');
  }
  /*
    Surrogate halfs (when alone) print badly in terminals:
      SELECT _ucs2 0xD800;
    Let's escape them as well.
  */
  if (wc >= 0xD800 && wc <= 0xDFFF)
    return FALSE;
  return TRUE;
}


static uint to_printable_8bit(uchar *dst, my_wc_t wc, uint bs)
{
  /*
    This function is used only in context of error messages for now.
    All non-BMP characters are currently replaced to question marks
    when a message is put into diagnostics area.
  */
  DBUG_ASSERT(wc < 0x10000);
  *dst++= (char) bs;
  *dst++= _dig_vec_upper[(wc >> 12) & 0x0F];
  *dst++= _dig_vec_upper[(wc >> 8) & 0x0F];
  *dst++= _dig_vec_upper[(wc >> 4) & 0x0F];
  *dst++= _dig_vec_upper[wc & 0x0F];
  return MY_CS_PRINTABLE_CHAR_LENGTH;
}


static uint my_printable_length(uint bslen, uint diglen)
{
  return bslen + (MY_CS_PRINTABLE_CHAR_LENGTH - 1) * diglen;
}


/**
  Encode an Unicode character "wc" into a printable string.
  This function is suitable for any character set, including
  ASCII-incompatible multi-byte character sets, e.g. ucs2, utf16, utf32.
*/
int
my_wc_to_printable_ex(CHARSET_INFO *cs, my_wc_t wc,
                      uchar *str, uchar *end,
                      uint bs, uint bslen, uint diglen)
{
  uchar *str0;
  uint i, length;
  uchar tmp[MY_CS_PRINTABLE_CHAR_LENGTH * MY_CS_MBMAXLEN];

  if (my_is_printable(wc))
  {
    int mblen= my_ci_wc_mb(cs, wc, str, end);
    if (mblen > 0)
      return mblen;
  }

  if (str + my_printable_length(bslen, diglen) > end)
    return MY_CS_TOOSMALLN(my_printable_length(bslen, diglen));

  if ((cs->state & MY_CS_NONASCII) == 0)
    return to_printable_8bit(str, wc, bs);

  length= to_printable_8bit(tmp, wc, bs);
  str0= str;
  for (i= 0; i < length; i++)
  {
    uint expected_length= i == 0 ? bslen : diglen;
    if (my_ci_wc_mb(cs, tmp[i], str, end) != (int) expected_length)
    {
      DBUG_ASSERT(0);
      return MY_CS_ILSEQ;
    }
    str+= expected_length;
  }
  return (int) (str - str0);
}


int
my_wc_to_printable_8bit(CHARSET_INFO *cs, my_wc_t wc,
                        uchar *str, uchar *end)
{
  /*
    Special case: swe7 does not have the backslash character.
    Use dot instead of backslash for escaping.
  */
  uint bs= cs->tab_to_uni && cs->tab_to_uni['\\'] != '\\' ? '.' : '\\';
  DBUG_ASSERT(cs->mbminlen == 1);
  /*
    Additionally, if the original swe7 string contains backslashes,
    replace them to dots, so this error message:
      Invalid swe7 character string: '\xEF\xBC\xB4'
    is displayed as:
      Invalid swe7 character string: '.xEF.xBC.xB4'
    which is more readable than what would happen without '\'-to-dot mapping:
      Invalid swe7 character string: '.005CxEF.005CxBC.005CxB4'
  */
  if (bs == '.' && wc == '\\')
    wc= '.';
  return my_wc_to_printable_ex(cs, wc, str, end, bs, 1, 1);
}


int
my_wc_to_printable_generic(CHARSET_INFO *cs, my_wc_t wc,
                           uchar *str, uchar *end)
{
  return my_wc_to_printable_ex(cs, wc, str, end, '\\',
                               cs->mbminlen, cs->mbminlen);
}


/*
  Convert a string between two character sets.
  'to' must be large enough to store (form_length * to_cs->mbmaxlen) bytes.

  @param  to[OUT]       Store result here
  @param  to_length     Size of "to" buffer
  @param  to_cs         Character set of result string
  @param  from          Copy from here
  @param  from_length   Length of the "from" string
  @param  from_cs       Character set of the "from" string
  @param  errors[OUT]   Number of conversion errors

  @return Number of bytes copied to 'to' string
*/

uint32
my_convert_using_func(char *to, size_t to_length,
                      CHARSET_INFO *to_cs, my_charset_conv_wc_mb wc_mb,
                      const char *from, size_t from_length,
                      CHARSET_INFO *from_cs, my_charset_conv_mb_wc mb_wc,
                      uint *errors)
{
  int         cnvres;
  my_wc_t     wc;
  const uchar *from_end= (const uchar*) from + from_length;
  char *to_start= to;
  uchar *to_end= (uchar*) to + to_length;
  uint error_count= 0;

  while (1)
  {
    if ((cnvres= (*mb_wc)(from_cs, &wc, (uchar*) from, from_end)) > 0)
      from+= cnvres;
    else if (cnvres == MY_CS_ILSEQ)
    {
      error_count++;
      from++;
      wc= '?';
    }
    else if (cnvres > MY_CS_TOOSMALL)
    {
      /*
        A correct multibyte sequence detected
        But it doesn't have Unicode mapping.
      */
      error_count++;
      from+= (-cnvres);
      wc= '?';
    }
    else
    {
      if ((uchar *) from >= from_end)
        break;  /* End of line */
      /* Incomplete byte sequence */
      error_count++;
      from++;
      wc= '?';
    }

outp:
    if ((cnvres= (*wc_mb)(to_cs, wc, (uchar*) to, to_end)) > 0)
      to+= cnvres;
    else if (cnvres == MY_CS_ILUNI && wc != '?')
    {
      error_count++;
      wc= '?';
      goto outp;
    }
    else
      break;
  }
  *errors= error_count;
  return (uint32) (to - to_start);
}


/*
  Convert a string between two character sets.
   Optimized for quick copying of ASCII characters in the range 0x00..0x7F.
  'to' must be large enough to store (form_length * to_cs->mbmaxlen) bytes.

  @param  to[OUT]       Store result here
  @param  to_length     Size of "to" buffer
  @param  to_cs         Character set of result string
  @param  from          Copy from here
  @param  from_length   Length of the "from" string
  @param  from_cs       Character set of the "from" string
  @param  errors[OUT]   Number of conversion errors

  @return Number of bytes copied to 'to' string
*/

uint32
my_convert(char *to, uint32 to_length, CHARSET_INFO *to_cs,
           const char *from, uint32 from_length,
           CHARSET_INFO *from_cs, uint *errors)
{
  uint32 length, length2;
  /*
    If any of the character sets is not ASCII compatible,
    immediately switch to slow mb_wc->wc_mb method.
  */
  if ((to_cs->state | from_cs->state) & MY_CS_NONASCII)
    return my_convert_using_func(to, to_length,
                                 to_cs, to_cs->cset->wc_mb,
                                 from, from_length,
                                 from_cs, from_cs->cset->mb_wc,
                                 errors);

  length= length2= MY_MIN(to_length, from_length);

#if defined(__i386__) || defined(__x86_64__)
  /*
    Special loop for i386, it allows to refer to a
    non-aligned memory block as UINT32, which makes
    it possible to copy four bytes at once. This
    gives about 10% performance improvement comparing
    to byte-by-byte loop.
  */
  for ( ; length >= 4; length-= 4, from+= 4, to+= 4)
  {
    if ((*(uint32*)from) & 0x80808080)
      break;
    *((uint32*) to)= *((const uint32*) from);
  }
#endif /* __i386__ */

  for (; ; *to++= *from++, length--)
  {
    if (!length)
    {
      *errors= 0;
      return length2;
    }
    if (*((unsigned char*) from) > 0x7F) /* A non-ASCII character */
    {
      uint32 copied_length= length2 - length;
      to_length-= copied_length;
      from_length-= copied_length;
      return copied_length + my_convert_using_func(to, to_length, to_cs,
                                                   to_cs->cset->wc_mb,
                                                   from, from_length, from_cs,
                                                   from_cs->cset->mb_wc,
                                                   errors);
    }
  }

  DBUG_ASSERT(FALSE); // Should never get to here
  return 0;           // Make compiler happy
}


size_t
my_convert_fix(CHARSET_INFO *to_cs, char *to, size_t to_length,
               CHARSET_INFO *from_cs, const char *from, size_t from_length,
               size_t nchars,
               MY_STRCOPY_STATUS *copy_status,
               MY_STRCONV_STATUS *conv_status)
{
  int cnvres;
  my_wc_t wc;
  my_charset_conv_mb_wc mb_wc= from_cs->cset->mb_wc;
  my_charset_conv_wc_mb wc_mb= to_cs->cset->wc_mb;
  const uchar *from_end= (const uchar*) from + from_length;
  uchar *to_end= (uchar*) to + to_length;
  char *to_start= to;

  DBUG_ASSERT(to_cs != &my_charset_bin);
  DBUG_ASSERT(from_cs != &my_charset_bin);

  copy_status->m_well_formed_error_pos= NULL;
  conv_status->m_cannot_convert_error_pos= NULL;

  for ( ; nchars; nchars--)
  {
    const char *from_prev= from;
    if ((cnvres= (*mb_wc)(from_cs, &wc, (uchar*) from, from_end)) > 0)
      from+= cnvres;
    else if (cnvres == MY_CS_ILSEQ)
    {
      if (!copy_status->m_well_formed_error_pos)
        copy_status->m_well_formed_error_pos= from;
      from++;
      wc= '?';
    }
    else if (cnvres > MY_CS_TOOSMALL)
    {
      /*
        A correct multibyte sequence detected
        But it doesn't have Unicode mapping.
      */
      if (!conv_status->m_cannot_convert_error_pos)
        conv_status->m_cannot_convert_error_pos= from;
      from+= (-cnvres);
      wc= '?';
    }
    else
    {
      if ((uchar *) from >= from_end)
        break; // End of line
      // Incomplete byte sequence
      if (!copy_status->m_well_formed_error_pos)
        copy_status->m_well_formed_error_pos= from;
      from++;
      wc= '?';
    }
outp:
    if ((cnvres= (*wc_mb)(to_cs, wc, (uchar*) to, to_end)) > 0)
      to+= cnvres;
    else if (cnvres == MY_CS_ILUNI && wc != '?')
    {
      if (!conv_status->m_cannot_convert_error_pos)
        conv_status->m_cannot_convert_error_pos= from_prev;
      wc= '?';
      goto outp;
    }
    else
    {
      from= from_prev;
      break;
    }
  }
  copy_status->m_source_end_pos= from;
  return to - to_start;
}


int my_strnncollsp_nchars_generic(CHARSET_INFO *cs,
                                  const uchar *str1, size_t len1,
                                  const uchar *str2, size_t len2,
                                  size_t nchars,
                                  uint flags)
{
  int error;
  len1= my_well_formed_length(cs, (const char *) str1,
                                  (const char *) str1 + len1,
                                  nchars, &error);
  len2= my_well_formed_length(cs, (const char *) str2,
                                  (const char *) str2 + len2,
                                  nchars, &error);
  DBUG_ASSERT((cs->state & MY_CS_NOPAD) == 0);
  return cs->coll->strnncollsp(cs, str1, len1, str2, len2);
}


int my_strnncollsp_nchars_generic_8bit(CHARSET_INFO *cs,
                                       const uchar *str1, size_t len1,
                                       const uchar *str2, size_t len2,
                                       size_t nchars,
                                       uint flags)
{
  set_if_smaller(len1, nchars);
  set_if_smaller(len2, nchars);
  DBUG_ASSERT((cs->state & MY_CS_NOPAD) == 0);
  return cs->coll->strnncollsp(cs, str1, len1, str2, len2);
}


uint my_ci_get_id_generic(CHARSET_INFO *cs, my_collation_id_type_t type)
{
  return cs->number;
}


LEX_CSTRING my_ci_get_collation_name_generic(CHARSET_INFO *cs,
                                             my_collation_name_mode_t mode)
{
  return cs->coll_name;
}


uint my_casefold_multiply_1(CHARSET_INFO *cs)
{
  return 1;
}


uint my_casefold_multiply_2(CHARSET_INFO *cs)
{
  return 2;
}


my_bool my_ci_eq_collation_generic(CHARSET_INFO *self, CHARSET_INFO *other)
{
  return FALSE;
}


/*
  Allocate a memory block for a new charset_info_st together with
  its name and its comment in a single once_alloc() call.
  Copy the name and the comment into the new block.
*/
struct charset_info_st *my_ci_alloc(MY_CHARSET_LOADER *loader,
                                    const LEX_CSTRING name,
                                    LEX_CSTRING *out_name,
                                    const LEX_CSTRING comment,
                                    LEX_CSTRING *out_comment)
{
  size_t nbytes= sizeof(struct charset_info_st) +
                 name.length + comment.length + 2;
  struct charset_info_st *csinfo;
  char *dst;
  if (!(csinfo= (struct charset_info_st*) (loader->once_alloc)(nbytes)))
    return NULL;
  dst= ((char*) csinfo) + sizeof(struct charset_info_st);

  memcpy(dst, name.str, name.length + 1);
  out_name->str= dst;
  out_name->length= name.length;
  dst+= name.length + 1;

  memcpy(dst, comment.str, comment.length + 1);
  out_comment->str= dst;
  out_comment->length= comment.length;

  return csinfo;
}
